Systems and methods for preloading a bearing

ABSTRACT

A system for providing a load on a bearing mounted to a shaft includes an attaching member releasably connectable to the shaft and a press mechanism in fluid communication with a source of fluid and configured to provide a compressive load to the bearing. The press mechanism includes a switch having a base and a piston in communication with the fluid such that an increase in a pressure of the fluid results in the piston extending upwardly from the base and a decrease in the pressure of the fluid results in the piston retracting toward the base. The switch includes a lower proximity sensor and a higher proximity sensor. The piston is configured to extend upwardly from the base past the lower proximity sensor and to trip the higher proximity sensor. The switch is configured to control the increase in the pressure in response to the piston tripping the higher proximity sensor.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of U.S. Ser. No. 15/661,808, filed onJul. 27, 2017, entitled “Systems and Methods for Preloading a Bearing”,which is a divisional of U.S. Ser. No. 15/071,753, filed on Mar. 16,2016, entitled “Systems and Methods for Preloading a Bearing”, now U.S.Pat. No. 9,764,453 issued on Sep. 19, 2017, the entire disclosure ofwhich is incorporated herein by reference.

This application is related to U.S. Ser. No. 12/492,826 filed on Jun.26, 2009, entitled “Systems and Methods for Preloading a Bearing andAligning a Lock Nut”, now U.S. Pat. No. 8,316,530 issued on Nov. 27,2012, the entire disclosure of which is incorporated herein byreference.

This application also relates to U.S. Ser. No. 13/683,571, filed on Nov.21, 2012, entitled “Methods for Preloading a Bearing and Aligning a LockNut”, now U.S. Pat. No. 8,650,752 issued on Feb. 18, 2014, the entiredisclosure of which is incorporated herein by reference.

This application also relates to U.S. Ser. No. 14/160,045, filed on Jan.21, 2015, entitled “Systems and Methods for Preloading a Bearing andAligning a Lock Nut”, now U.S. Pat. No. 8,904,646 issued on Dec. 9,2014, the entire disclosure of which is incorporated herein byreference.

This application also relates to U.S. application Ser. No. 11/341,948,filed Jan. 27, 2006, and titled “Method and Apparatus for Preloading aBearing”, issued as U.S. Pat. No. 7,559,135 on Jul. 14, 2009, the entiredisclosure of which is incorporated herein by reference.

This application also relates to U.S. application Ser. No. 11/354,513,filed Feb. 15, 2006, and titled “Method, Apparatus, and Nut forPreloading a Bearing”, issued as U.S. Pat. No. 7,389,579 on Jun. 24,2008, the entire disclosure of which is incorporated herein byreference.

This application also relates to U.S. Ser. No. 12/033,548, filed on Feb.19, 2008, entitled “Axle Nut”, now U.S. Pat. No. 8,961,090 issued onFeb. 24, 2015, the entire disclosure of which is incorporated herein byreference.

This application also relates to U.S. Ser. No. 12/492,926, filed Jun.26, 2009, entitled “Methods for Preloading a Bearing”, now U.S. Pat. No.8,359,733 issued on Jan. 29, 2013, the entire disclosure of which isincorporated herein by reference.

This application also relates to U.S. Ser. No. 14/305,830, filed Jun.16, 2014, entitled “Lock Nut System”, now U.S. Pat. No. 9,200,673 issuedDec. 1, 2015, the entire disclosure of which is incorporated herein byreference.

This application also relates to U.S. Ser. No. 14/305,673, filed Jun.16, 2014, entitled “Method, Apparatus, and Nut for Preloading ABearing”, now U.S. Pat. No. 9,200,672 issued Dec. 1, 2015, the entiredisclosure of which is incorporated herein by reference.

This application also relates to U.S. Ser. No. 14/814,086, filed Jul.30, 2015, entitled “Apparatus for Preloading A Bearing”, now U.S. Pat.No. 9,618,049 issued Apr. 11, 2017, the entire disclosure of which isincorporated herein by reference.

This application also relates to U.S. Ser. No. 14/852,100, filed Sep.11, 2015, entitled “Method, Apparatus, and Nut for Bearing”, now U.S.Pat. No. 9,651,094 issued May 16, 2017, the entire disclosure of whichis incorporated herein by reference.

This application also relates to U.S. Ser. No. 14/952,663, filed Nov.25, 2015, entitled “Method, Apparatus, and Nut for Bearing”, now U.S.Pat. No. 9,574,612 issued Feb. 21, 2017, the entire disclosure of whichis incorporated herein by reference.

This application also relates to U.S. Ser. No. 15/441,520, filed Feb.24, 2017, entitled “Method for Preloading a Bearing”, now U.S. Pat. No.9,797,411 issued Oct. 24, 2017, the entire disclosure of which isincorporated herein by reference.

This application also relates to U.S. Ser. No. 15/714,145, filed Sep.25, 2017, entitled “Apparatus for Preloading a Bearing”, published asU.S. Publication No. US 2018-0045244-A1 published on Feb. 15, 2018, theentire disclosure of which is incorporated herein by reference.

This application also relates to U.S. Ser. No. 15/928,963, filed Mar.22, 2018, entitled “Apparatus for Preloading a Bearing”, the entiredisclosure of which is incorporated herein by reference.

This application is also related to U.S. Ser. No. 14/533,143, filed onAug. 8, 2014, entitled “Systems and Methods for Preloading A Bearing andAligning A Lock Nut”, now U.S. Pat. No. 9,217,461 issued Dec. 22, 2015,the entire disclosure of which is incorporated by reference);

This application also relates to U.S. Ser. No. 15/071,570 filed Mar. 16,2017, entitled “Systems and Methods for Preloading a Bearing andAligning a Lock Nut”, now U.S. Pat. No. 9,908,223 issued Mar. 6, 2018,the entire disclosure of which is incorporated herein by reference.

This application also relates to U.S. Ser. No. 15/885,988 filed Feb. 1,2018, entitled “Systems and Methods for Preloading a Bearing andAligning a Lock Nut”, the entire disclosure of which is incorporatedherein by reference.

This application also relates to U.S. Ser. No. 15/071,584, filed Mar.16, 2016, entitled “Systems and Methods for Preloading a Bearing”, nowU.S. Pat. No. 9,599,164 issued on Mar. 21, 2017, the entire disclosureof which is incorporated herein by reference.

This application also relates to U.S. Ser. No. 29/558,261, filed Mar.16, 2016, entitled “Retaining Ring Pliers”, now U.S. Design Pat. No. D789,169 issued Jun. 14, 2017, the entire disclosure of which isincorporated herein by reference.

This application also relates to U.S. Ser. No. 15/416,683, filed Jan.26, 2017, entitled “Systems and Methods for Preloading a Bearing”,published as U.S. Publication No. US-2017-0268572-A1 on Sep. 21, 2017,the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates, generally, to methods and apparatus forpreloading antifriction bearings in drive trains, particularly, topreloading and adjusting bearings while monitoring the preload beingapplied.

BACKGROUND OF THE INVENTION

Various means have been devised to simplify the adjustment of axlebearings, specifically, truck axle bearings. It is generally acceptedthat in some bearing installations, for example, axle bearings, the lifeof the bearing will be optimized if the adjustment is made for a slightaxial compressive deflection, for example, about 0.003 inches (wherethis amount is the compressive deflection of the two bearings combined),which is often referred to as “a three thousandths preload.” Typicalprior art methods of creating these preloads are obtained by applyingspecified torques to the bearing assembly, for example, by tighteningthe nut that retains the bearings. However, for several reasons, it istypically extremely difficult to achieve such preload settings underactual in-field conditions, such as in a mechanic shop. For example, theassembly of a heavy truck wheel onto a wheel hub assembly is arelatively cumbersome procedure that hinders the mechanic. Moreover, thewheel hub assembly always includes at least one inner seal, usually alip type of seal, which can impose a resistive drag torque component tothe preload torque, particularly when the seal is new.

Lock nut systems are often utilized to retain a wheel or hub assembly,including axle bearings, on a shaft. Such lock nut systems may beconnected to a shaft and inhibit rotation of a retaining nut relative tosuch shafts. For example, such systems are often utilized on motorvehicles, such as axles and wheel ends. Typically, a lock nut will beengageable with a locking member or keeper which inhibits movement ofthe nut relative to the shaft. The locking member may include aprotruding portion which extends into a slot or receiving portion of ashaft. The locking member may also engage the nut such that there islittle or no movement between the nut and shaft.

Thus, a need exists for providing accurate and repeatable procedures anddevices for providing and adjusting bearing preload and for adjustinglock nut systems configured to retain preloaded bearings.

SUMMARY OF THE INVENTION

The present provides, in a first aspect a system for providing a load ona bearing mounted to a shaft which includes an attaching memberreleasably connectable to the shaft and a press mechanism in fluidcommunication with a source of fluid and configured to provide acompressive load to the bearing. The press mechanism includes a switchhaving a base and a piston in communication with the fluid such that anincrease in a pressure of the fluid results in the piston extendingupwardly from the base and a decrease in the pressure of the fluidresults in the piston retracting toward the base. The switch includes afirst lower proximity sensor and a second higher proximity sensor. Thepiston is configured to extend upwardly from the base past the firstlower proximity sensor and to trip the second higher proximity sensor.The switch is configured to control the increase in the pressure inresponse to the piston tripping the higher proximity sensor.

The present invention provides in a second aspect, a method for use inproviding a load on a bearing mounted to a shaft which includes mountingan attaching mechanism to an end of the shaft and coupling the pressmechanism to the attaching member with the press mechanism configured toprovide a compressive load to the bearing. The press mechanism iscoupled to a source of fluid and a pressure of the fluid is increasedfrom the source to the press mechanism to provide a compressive load tothe bearing. The increase in the pressure causes a piston of a switch ofthe press mechanism to extend upwardly from a base of the switch to tripa second higher proximity sensor of the switch. The switch controls thepressure of the fluid to control the load on the bearing in response tothe piston tripping the higher proximity sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the invention, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention will be readily understood from thefollowing detailed description of aspects of the invention taken inconjunction with the accompanying drawings in which:

FIG. 1 is a right side elevation view, partially in cross section, ofwheel hub assembly engaging a bearing preload apparatus according to oneaspect of the invention;

FIG. 2 is a close up view of a portion of FIG. 1;

FIG. 3 is a top plan view, partially in cross section of a portion ofthe assembly shown in FIG. 1;

FIG. 4 is an exploded perspective view of the assembly of FIG. 1 withportions of the wheel hub assembly removed;

FIG. 5 is perspective view of the assembly of FIG. 1 with portions ofthe wheel hub assembly removed;

FIG. 6 is a perspective view of the apparatus of FIG. 5 with extendingarms of the preload apparatus extended relative to the depiction in FIG.5;

FIG. 7 is a perspective view of the apparatus of FIG. 6 with theextending arms extended further around a lock nut to engage a bearing;

FIG. 8 is an elevational view of a lock nut system which includes a locknut having a keeper and a keeper retaining member engaged with the nutaccording to an aspect of the present invention;

FIG. 9 is an elevational view of the keeper retaining member of FIG. 8;

FIG. 10 is a perspective view of a pressure buffer switch of theapparatus of FIG. 1;

FIG. 11 is a perspective view of the switch of FIG. 10 with a pistonextension extending from a cavity thereof past a first proximity sensor;

FIG. 12 is a side cross-sectional view of the switch of FIG. 10;

FIG. 13 is a side cross-sectional view of the switch of FIG. 11; and

FIG. 14 is a side cross-sectional view of the switch of FIG. 13 with thepiston extension extending in the proximity of a second proximitysensor.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the principals of the present invention, system andmethods for adjusting bearings mounted on a shaft and aligning lock nutsfor retaining such bearings are provided.

In an exemplary embodiment depicted in FIG. 1, a wheel hub assembly 10engages a bearing preload apparatus 20. Some of a section of thehardware has been removed to reveal inner structure to facilitatedisclosure of the invention. For the sake of illustration, the wheelassembly that would typically be mounted to wheel hub assembly 10 isomitted in these figures.

Wheel hub assembly 10 is an assembly that would typically be found on afront or rear axle of a cab or tractor of a tractor-trailer, or an axleof a trailer. However, aspects of the invention are not limited to usefor vehicle bearings. As will generally be understood by those skilledin the art, aspects of the invention may be used to service bearings andbearing assemblies in any machine or device that employs bearings,including, but not limited to: powertrains, transmissions, machinecomponents, on- and off-road vehicles, aircraft wheels, marine drives,spacecraft, conveyor rolls, and windmills, among others. According toaspects of the present invention, preload apparatus 20 may be used inthese and any other assembly for which bearing preload and/or endplay isdesired, for example, any assembly that utilizes thrust and radial loadcarrying bearings that are indirectly mounted.

As shown in FIG. 1-4, for example, wheel hub assembly 10 includes awheel hub or, simply, a hub 12, a threaded shaft, axle, or spindle 14.As is typical, spindle 14 is mounted on two antifriction bearings andspindle 14 includes an exposed end 13, which is typically threaded.Spindle 14 typically includes a retaining nut 11 threaded to exposed end13.

As shown in FIGS. 1-3, as is typical of bearings, an outboard bearing 16includes an inner race (or cone) 15, an outer race (or cup) 17, aplurality of rollers 22, and a roller cage. Similarly, an inboardbearing 18 includes an inner race (or cone) 19, an outer race (or cup)21, a plurality of rollers 26, and roller cage. As shown in FIG. 2,outboard bearing 16 is positioned, for example, by an interference fit,into an annular cavity 29. The details of an inboard bearing and anoutboard bearing are described and depicted in co-owned U.S. Pat. No.7,303,367, issued Dec. 4, 2007 (application Ser. No. 11/029,531 filedJan. 5, 2005), entitled “Lock Nut System”; U.S. Publication No.2007/0177829A1, published Aug. 2, 2007, (application Ser. No. 11/341,948filed Jan. 27, 2006), entitled “Method and Apparatus for Preloading aBearing”; and U.S. Pat. No. 7,389,579, issued Jun. 24, 2008 (applicationSer. No. 11/354,513, filed Feb. 15, 2006), entitled “Method, Apparatus,and Nut for Preloading a Bearing”, the entirety of which areincorporated herein by reference.

As depicted in FIGS. 1-8, for example, retaining nut 11 may be a lockingnut as disclosed in co-owned U.S. Pat. No. 7,303,367 (application Ser.No. 11/029,531 filed Jan. 5, 2005), entitled “Lock Nut System”; U.S.Publication No. 2007/0177829A1 (application Ser. No. 11/341,948 filedJan. 27, 2006), entitled “Method and Apparatus for Preloading aBearing”; and U.S. Pat. No. 7,389,579 (application Ser. No. 11/354,513,filed Feb. 15, 2006), entitled “Method, Apparatus, and Nut forPreloading a Bearing”. In the conventional art, retaining nut 11typically is used to secure a wheel (not shown) or hub assembly to anon-rotating axle or spindle 14. However, in aspects of the presentinvention, retaining nut 11 may be useful in varying the preload and/orendplay of bearing 16. Though bearing 16 is illustrated as a taperedroller bearing, aspects of the invention may be applied to other typesof antifriction bearings for which it is desirable to provide preloadand/or endplay, for example, spherical roller bearings, deep groove ballbearings, and the like.

As depicted in FIGS. 8-9, a keeper 530 is engageable with retaining nut11 and is connected to a keeper retaining member 540. A projection 535of keeper 530 extends through an opening 545 in retaining member 540when connected. Projection 535 extends substantially perpendicular to aplane of retaining member 540. Projection 535 may be deformed bypressure applied on a top thereof (i.e. in a direction substantiallyperpendicular to the plane of retaining member 540) to connect retainingmember 540 with keeper 530 similar to the way a rivet is utilized, aswill be understood by those skilled in the art. Keeper 530 and retainingmember 540 engage retaining nut 11. For example, keeper 530 includeskeeper teeth 520 which are configured to engage engaging teeth 511 ofretaining nut 11. Keeper 530 may also include an engaging member 534which protrudes radially inwardly relative to retaining nut 11 to engagea shaft slot 5 (FIGS. 4-5), keyway, groove or other engaging portion ofa shaft (e.g., spindle 14). Thus, engaging member 534 may inhibitmovement of keeper 530 relative to a shaft (e.g., spindle 14) and theengagement of engaging teeth 511 with keeper teeth 520 may inhibitmovement of keeper 530 relative to retaining nut 11. Accordingly,movement of retaining nut 11 relative to the shaft is prevented orreduced. Keeper 530 and/or nut 11 may be molded or formed of powderedmetal, for example.

Keeper retaining member 540 may engage a slot 561 of retaining nut 11.For example, a first leg 542 and a second leg 543 may be received inslot 561. For example, slot 561 may have a radial depth of about 0.050inches. Further, a nose 544 of retaining member 540 may be received inslot 561. Retaining member 540 when received in slot 561 may alignkeeper 530 such that keeper teeth 532 are engaged with engaging teeth511. Further, retaining member 540 provides resistance in an axialdirection relative to retaining nut 11 thereby inhibiting movement ofkeeper 530 axially away from a shoulder 524 toward an outer surface 522.

Retaining member 540 may be elastically deformable to allow it to bereceived in slot 561. For example, first leg 542 and second leg 543 maybe deformed (e.g., in a direction substantially perpendicular to theaxis of retaining nut 11) toward one another prior to being insertedaxially past outer surface 522 of retaining nut 11 to allow retainingmember 540, and keeper 530 to be attached thereto. First leg 542 andsecond leg 543 may then be elastically returned toward slot 561. Firstleg 542 may also include a gripping member 568 and second leg 543 mayinclude a second gripping member 569. The gripping members aresubstantially parallel to one another and are aligned at about 90degrees from a plane of retaining member 540. A user may move the legs(i.e., first leg 542 and second leg 543) toward one another as describedabove to allow the retaining member to be received in slot 561. In oneexample, a user may use a tool (e.g., a type of pliers, such as needlenose pliers) which is inserted into openings 611 and 612 (FIG. 5) toallow the tool to grip the legs to move ends 610 toward one anotherthereby allowing the legs to be inserted into slot 561. In one example,tool 7 disclosed in co-owned U.S. Pat. No. 9,599,164 is usable for thispurpose.

Also, first leg 542 may include a protruding portion 560 which protrudesradially relative to a rounded portion 565 of retaining member 540.Similarly, second leg 543 may include a protruding portion 562.Protruding portion 560 and protruding portion 562 may extend into slot561 to engage retaining member 540 with slot 561. Further, protrudingportion 560 may include a groove 566 and protruding portion 562 mayinclude a groove 567. For example, retaining member 540 may be formed ofstamped sheet metal, and may have a thickness in a range between0.040-0.050 inches, as will be understood by those skilled in the art.Alternatively, retaining member 540 could be formed of other materials(e.g., powdered metal) and/or formed in other shapes to allow retainingmember 540 to be received in slot 561 and to be connected to keeper 540via projection 535. Further, keeper 530 may be formed or molded ofpowdered metal, for example. Alternatively, keeper 530 and retainingmember 540 could be formed integral or monolithic relative to oneanother.

Further, keeper 530 and/or nut 11 may be fabricated from any one or moreof the structural metals, for example, carbon steel or stainless steel.Nut 11 may be fabricated by machining from a billet or plate, by forgingor casting and then finished machining, or fabricated by conventionalpowder metallurgy techniques. In one aspect, when formed by powdermetallurgy, the material may be FC 0208, or its equivalent. Nut 11 mayalso be surface hardened for example, induction hardened, carburized, ornitrided, among other surface hardening methods; in one aspect, theexposed surfaces on end 241 of nut 220 may be hardened, for example,induction hardened.

Returning to FIGS. 1-5, preload apparatus 20 includes an attachingmechanism, such as a shaft or rod 40 engageable with spindle 14 by acollar 46, and a press mechanism 44 for providing a compressive load tobearing 16. In addition, aspects of the invention provide means formonitoring the preload on the bearings to, for example, ensure that thedesired preload is provided, in contrast to the unreliable and ofteninaccurate assumed preloading of the prior art.

Rod 40 may be configured to attach to exposed end 13 of shaft 14, forexample, by collar 46, though other attachment means may be used. Pressmechanism 44 may include an adjustment handle 50 which may be connectedto rod 40 to facilitate rotation of rod 40 and/or collar 46 to connectpress mechanism 44 to shaft 14. Such connection may also be performed bya servo motor or other mechanism for rotating rod 40 and/or collar 46 toconnect press mechanism 44 to shaft 14.

Press mechanism 44 may provide a compression force via a nut asdescribed in co-owned U.S. Pat. No. 8,316,520 relative to a nut 48depicted therein or via a hydraulic, pneumatic or other means ofproviding such a force.

As shown in FIGS. 3-7, press mechanism 44 includes loading arms 210. Acompressive load from press mechanism 44 is transmitted to bearing 16,and to bearing 18, by loading arms 210. Further, loading arms 210 workin conjunction with retaining nut 11 to provide a load to outboardbearing 16 (e.g., an inner race 15 thereof). Retaining nut 11 may have arecess that exposes the surface of inner race 15 and permits contact by,for example, loading arms 210. For example, as depicted in FIGS. 1-7,nut 11 may have a bottom curve or recessed portion 111 such that abottom end of nut 11 has a smaller diameter than the remainder thereof.Loading arms 210 may thus transmit the compressive load from pressmechanism 44 (i.e., around nut 11) to bearing 16. In an unillustratedexample, bearing 16 could be exposed thereby allowing press mechanism 44to be used with a conventional axle nut, as shown for example in FIG. 3of co-owned application U.S. Pat. No. 7,389,579. However, when bearing16 would be concealed by such a conventional axle nut, retaining nut 11may be used instead thereof according to aspects of the invention.

As depicted in FIGS. 3-7, for example, loading arms 210 extend from abase 400 and include a first arm 212 and a second arm 213. In thisaspect of the invention, arms 210 are adapted to transmit a load frompress mechanism 44 to the bearing 16. In one aspect, arms 210 may bemoveable or deflectable to facilitate assembly of arms 210 intoengagement with bearing 16. For example, arms 210 may include amodification to arms 212 and 213 that permits arms 212 and 213 todeflect to avoid interference with nut 11. In an example, arms 210 maybe pivotally mounted to base 400 or another portion of press mechanism44 to allow lateral movement of the arms such that the arms may engagebearing 16. Arms 210 may include projections 225, 226, respectively, forexample, arcuate projections adapted to engage the arcuate shape ofbearing 16 (e.g., an inner race thereof) as described previouslyrelative to extensions 212, 213 of co-owned U.S. Pat. No. 8,650,757,issued on Feb. 18, 2014, and titled “Methods for Preloading a Bearingand Aligning a Lock Nut”. Arcuate projections 225, 226 may be radiusedto provide the same curvature of bearing 16, for example, a radius ofbetween about 1¼ inches and about 3 inches. The shape of arms 210including projections 225, 226 may ensure that the compressive loadapplied by press mechanism 44 is transmitted to bearing 16 and not borneby nut 11. Minimizing or preventing contact between extensions 212, 213and nut 11 also permits nut 11 to be freely rotated without contact withextensions 212, 213.

Press mechanism 44 may include a wrench 230 having teeth 235 engageablewith teeth 511 of nut 11 to allow a rotation of nut 11 via a controllercontrolling a rotation of nut 230. Wrench 230 may surround collar 46 andbe extendable away from base 400 toward nut 11 and retractable in anopposite direction. Teeth 235 may engage teeth 511 when wrench 230 isextended to contact nut 11.

Although only two arms 212, 213 are illustrated in FIGS. 3 and 10-11,according to one aspect of the invention, two or more arms 212, 213 maybe mounted to, or otherwise extend from, base 400 of press mechanism 44.For example, three or more extensions arms may be provided, for example,uniformly spaced about base 400 about an axis coaxial to an axis ofshaft 14 and/or rod 40. In one aspect of the invention, arms 212, 213may include spring-loaded mountings to base 400 whereby arms 212, 213are biased into a position of engagement with race 15. Press mechanism44 may be any apparatus that is configured to provide a compressive load(e.g., utilizing a nut) to outboard bearing 16 (e.g., an inner racethereof). Further, press mechanism 44 may include a load sensor or anymeans for monitoring the compressive load transferred to bearing 16. Forexample, the indication of the compressive load transferred by pressmechanism 44 may be provided mechanically, for example, by compressionsprings having a known spring constant, for example, coil springs ordisc springs, and a deflection indicator, for example, a dial indicator,as is known in the art. In this aspect, the dial indicator may bemounted to detect and indicate the compression of one or more springspositioned in press mechanism 44 due to the advancement of nut 48, andthe compression load calculated from the deflection indicated and theknown spring constant of the springs used. The load sensor may be wiredto an appropriate controller or processor and display to, for example,provide a digital readout of the compressive load to the mechanicoperating preload device 20. The transmission of signals from the sensormay also be practiced wirelessly, for example, by means of an RF signal.This aspect of the invention may also provide a reliable and repeatablemeans for monitoring the preload provided to bearing 16.

In another aspect of the invention, press mechanism 44 may include atleast one fluid, for example, a gas, such as air; or a liquid, such as,water, oil, or hydraulic fluid, the pressure of which can be detectedand monitored, for example, by means of a pressure gage, pressuresensor, or a mechanical indicator. In one aspect, the fluid pressure maycomprise the source of compressive load on bearing 16. In such anembodiment, the fluid may be retained in a cavity for example, adeformable cavity, such as a bladder or hose, for example, an airspring; or a cavity having rigid walls and at least one moveable wall,for example, as in a cylinder and piston. In one aspect, the deformablecavity or air spring may be made of molded rubber, somewhat like aninner tube.

When air is used as the fluid, the air may be provided by conventional“shop air” at a pressure of about 100 psig. The pressure of the fluid inthe deformable cavity may be monitored by means of sensor or pressuregauge, for example, a pressure gauge mounted to a nozzle inserted on athe wall of the deformable or non-deformable cavity. In one aspect, amechanical indicator may be activated, for example, a lever deflectedwhen the desired fluid pressure in press mechanism 44 is reachedadvising the mechanic.

As discussed previously, press mechanism 44 and rod 40 thereof may beadapted to attach to exposed end 13 of spindle 14. Though this may beeffected by many conventional means, including welding and mechanicalfasteners, in the aspect of the invention shown in FIGS. 1-4, rod 40 isattached to end 13 of spindle 14 by collar 46. In the aspect shown,collar 46 is mounted to rod 40 by internal threads 47 in collar 46 thatthread onto external threads 49 on rod 40. Collar 46 also includes asecond set of internal threads 45 that engage external threads 51 onspindle 14. In one aspect, only 2 or 3 external threads 51 need beengaged by collar 46. According to one aspect, multiple collars 46having varying diameters may be provided to accommodate varyingdiameters of spindle 14. Each of these collars 46 may be adapted toengage external threads 49 on rod 40.

Rod 40, housing 42, collar 46, arms 50, housing 52, piston 54, andhousing 42 may be fabricated from any conventional structural metal, forexample, iron, steel, stainless steel, aluminum, titanium, nickel,magnesium, brass, or bronze, among others.

In one aspect of the invention, preload apparatus 20 may be used toapply and monitor a preload to outboard bearing 16. In a typicalprocedure, a wheel (not shown) may be dismounted from hub assembly 10,for example, which was mounted to studs on hub 12, as exemplified bystud 100 in FIGS. 1-3. Nut 11 may be loosened or hand tightened prior tomounting apparatus 20, though any light load on nut 11 will typically berelieved with application of tension to spindle 14 by means of rod 40.

For example, a torque wrench and socket may be utilized to torque nut 11and seat the bearings. The nut may then be tightened to a “hand tight”position followed by loosening of the nut by backing it off about ¼turn. Alternatively, such tightening and loosening may be done usingservo controlled wrench tools (e.g., wrench 230) which perform suchtasks in response to a command by a user or which may be automaticallyperformed in response to a set of instructions programmed and stored inthe controller or a second controller or computer storage coupled to thecontroller.

Apparatus 20 may then be mounted to hub assembly 10 by attaching rod 40to spindle 14 by means of collar 46. Arms 210 may then be automaticallyadvanced by press mechanism 44 such that the arms are brought intocontact with bearing 16 (e.g., an inner race thereof) as depicted inFIGS. 5-7 which a movement of arms 210 toward bearing 16 and around nut11. FIG. 7 shows a same position of arms 210 as FIG. 3. In one example,press mechanism may then apply 4000 lbs force to bearings.

Such force may be generated and transmitted by press mechanism 44 usingany of various mechanisms including those described in co-owned U.S.Pat. No. 8,316,530 relative to press mechanism 44. In one example, theloading of bearing 16 may be initiated by advancing, that is tightening,a nut (such as nut 48 described in Patent '530) against housing 52 viabearing 62, for example, by means of arms 50. The buildup of pressure incavity 56 as indicated by pressure indicator 60 may be monitored by themechanic as described in co-owned U.S. Pat. No. 8,316,530. The nut maybe tightened and loosened manually or by an electronically controlledservo wrench controlled by a controller preprogrammed or operated inreal time by a user, for example.

Pressure is applied by press mechanism 44 until a target pressure isachieved. The hub assembly may be rotated at least once to provideproper seating of the rollers in bearing 16. Alternatively, the bearingscould be automatically rolled utilizing a separate bearing rollingmechanism not described herein.

A desired preload may then be provided (e.g., automatically controlledby the controller) by press mechanism 44 to the bearings. The controllermay cause a servo motor to actuate wrench tools (e.g., wrench 230) andtorque the nut (e.g., nut 11) to “finger tight” or a wrench 230 could becontrolled by a controller to provide such a preload. If endplay isdesired, a servo motor (e.g., coupled to wrench 230 or a separate servowrench) may back the nut off to a desired endplay setting. Uponcompletion of the preloading, apparatus 20 may be removed from wheel hubassembly 10 and, keeper 530 and retaining member 540 may be engaged withretaining nut 11 and spindle 14 such that keeper teeth 520 engage teeth511 of nut 11 and engaging member 534 of keeper 530 engage shaft slot 5of spindle 14.

The preloading of the bearings as described above is advantageousrelative to endplay adjustment but was rarely recommended prior to thepresent invention due to the difficulty of creating and verifying acorrect preload site. A load sensor such as a pressure indicator orgauge (not shown) may be used along with the selective positioning ofretaining nut 11 on spindle 14 (e.g., using locating laser beamsproduced by locating optical sending units and markings 510; or wrenchcontrolled by a controller described in co-owned U.S. Pat. No. 9,908,223issued Mar. 6, 2018) provide for a repeatable correct and accuratepreload setting.

In another example, press mechanism 44 may apply pressure by fluidpressure to provide the compressive load to bearing 16. In this aspectof the invention, the compressive force provided by the nut describedrelative to Patent '530 may be replaced by fluid pressure provided topress mechanism 44. For example, as depicted in FIGS. 1-4, pressmechanism 44 includes a housing 52 and a movable piston 54 mounted foraxial movement in housing 52. In this aspect of the invention, aninternal cavity 56 is provided in housing 52. Internal cavity 56 is atleast partially filled, for example, substantially completely filled,with a fluid, for example, a gas, air, oil, water, and the like, thatproduces a hydrostatic pressure when fluid pressure is provided tointernal cavity 56 receiving piston 54 via a pump (not shown),pressurized shop gas, or otherwise. Such pressure may cause movement ofpiston 54 which may be mechanically coupled to arms 210 to provide theload to bearing 16. A reduction in such pressure may cause a retractionof piston 54 and/or a reduction in the load.

Piston 54 may be provided with one or more seals (not shown), forexample, one or more wiper seals, to minimize or prevent the leakage offluid from housing 52. Also, cavity 56 bounded by housing 52 may provideclearance for the displacement of piston 54 therein.

In one aspect, the fluid pressure (e.g., to cavity 56 of housing 52 ofpress mechanism 44) may be provided by a conduit or hose. The hose maysupply fluid, for example, hydraulic fluid, from a pressurized supply,for example, a pump controlled by a controller. The fluid supplied tothe hose may vary from 500 to 3000 psig.

Such a press mechanism applying pressure by fluid pressure may be usedto automatically regulate the compressive load on bearing 16, forexample, by regulating the pressure introduced to press mechanism 44through the hose. In one aspect, the invention may include an automaticcontroller, for example, a PID controller, personal computer, or PLCcontroller adapted to regulate the pressure in the hose. For example,the predetermined preload and the parameters of the bearing being loadedmay be entered into the controller and, after mounting a rod similar torod 40, housing 42 and a press mechanism to bearing 16 (e.g., an innerrace thereof), the controller may automatically ramp up the fluidpressure to provide the desired preload or to verify an existingpreload. This aspect of the invention may be suitable for productionline applications, among others.

In one aspect, the fluid provided by the hose may be provided by apressure increasing device, for example, a pressure intensifier, thatis, a device that converts one pressure to a higher pressure. Forexample, the pressure-increasing device may be provided with a pressuresupply of, for example, 100 psig (for instance, shop air) and increasedto, for example, 2000 psig hydraulic fluid, which is then supplied tothe hose. Other sources of high-pressure fluid may be provided accordingto aspects of the invention.

In an example, press mechanism 44 may include a switch 300 for use incontrolling the load on bearing 16. Switch 300 may be in fluidcommunication with cavity 56 and thereby a source of fluid (e.g., viathe hose described above) utilized to provide fluid pressure to applythe load to the bearing. Switch 300 may be coupled to a controller ormay include a controller therein to regulate the compressive load onbearing 16, for example, by regulating the pressure (e.g., hydraulic orair) introduced into cavity 56 to drive piston 54 as described above.

As depicted in FIGS. 10-14, switch 300 may include a fluid input 310 influid communication with cavity 56 via a conduit (e.g., a hose), forexample. Switch 300 may include a first lower sensor (e.g., a proximitysensor) 320, a second upper sensor (e.g., a proximity sensor) 330 and aswitch piston 340. A fluid pressure in cavity 56 may cause fluid to flowto an interior 305 (FIG. 13) of switch 300 to cause a switch piston 340,and an extending portion 350 thereof, to rise upwardly in response to anincrease in pressure in cavity 56 and to retract downwardly in responseto a decrease in such pressure.

First lower sensor 320 and second upper sensor 330 may be proximitysensors that are configured to detect a presence of extending portion350 near such sensors, such as when the extending portion approachesand/or extends past such sensors. For example, the sensors may detectthe proximity of extending portion 350 by emitting an electromagneticfield or a beam of electromagnetic radiation while a receiver portionthereof detects if a change in a field has occurred or the occurrence ofa reflection or return signal. Other examples include capacitive orphotoelectric proximity sensors. In a further example, the sensors maybe electrical contact sensors and extending portion 350 could contacteach sensor to indicate a presence thereof.

The presence of first lower sensor 320 and second upper sensor 330allows a control of an application of pressure on bearing 16. Forexample, as fluid flows to cavity 56 and pressure therein builds, fluidmay flow and build in interior 305 of switch 300 causing switch piston340 including extending portion 350 to rise. Sensor 320 and sensor 330may detect a presence of extending portion 350 as the extending portionscome near each particular sensor. In one example when the pressure incavity 56 rises extending portion 350 may rise to pass sensor 320 andsensor 330, and when the pressure decreases extending portion 350 maypass the sensors or could stop between the sensors. For example, adesired pressure may be present when the extending portion is locatedbetween the sensors and a controller coupled to the sensors and a pumpmay control the pump to provide fluid to cavity 56 to control a load onthe bearing via maintenance of extending portion 350 between sensor 320and 330.

For example, a ratio of a weight of an entirety of switch piston 340 toa plunger end 341 may be calibrated to a certain pressure; e.g., if theplunger end were exactly 1 square inch and the weight were exactly 100pounds, a buffering pressure may be set at 100 psi. In an example, byreducing the surface area of plunger end 341 from 1 square inch to 0.5square inches the buffering pressure would then be at 200 psi. Thebuffering pressure could be set to the application. In an example,either 250 or 500 pounds of force could be held on a bearing/hubassembly. In another example, if a piston (e.g., piston 54) of a tool(e.g., press mechanism 44) had 4 square inches of surface area, 125 psimay be needed to be maintained by a Pressure Buffering Switch (e.g.,switch 300), which may be accomplished by a piston weighing 125 poundswith a 1 square inch plunger (e.g., plunger end 341). In anotherexample, a piston (e.g., piston 54) weighing 25 pounds could be combinedwith a plunger (e.g., plunger end 341) of 0.2 square inch.

Further, relative to press mechanism 44, an output force may be measuredto calibrate frictional and other losses out of the system by adjustinga piston weight (e.g., piston 54) until a precise force output isachieved.

In another example, a roll-in pressure (hydraulic or pneumatic) isapplied to the bearing via fluid pressure (e.g., a pressure of 4000 lbs)being provided to piston 54 which causes a pressure in cavity 56 to riseand switch piston 340 to rise to an uppermost end of stroke as depictedin FIGS. 11 and 14, for example.

The system of pressure in cavity 56 coupled to interior 305 may becalibrated such that a desired preload on the bearing occurs whenextension 350 (e.g., a top end 355 thereof) is located verticallybetween sensors 320 and 330. For example a load on the bearing may be500 lbs when top end 355 is located between the sensors. In an example,after the roll-in pressure described above is applied, the load andpressure may be reduced until top end 355 is located between sensors 320and 330. The vertical distance between the sensors may provide a bufferswitch such that if the pressure in cavity 56 and interior 305 drops tothe level of sensor 320 an action may be taken. For example, upon end355 being detected (e.g., via a proximity detector of sensor 320) in aproximity of sensor 320 then flow and the corresponding pressure tocavity 56 and interior 305 may be increased or restarted (e.g., via apump) until end 355 is in a vicinity of sensor 330 (e.g., as detected bya proximity detector in sensor 330) after which the flow and pressuremay be stopped to maintain the desired pressure, i.e., as when end 355is between sensors 320 and 330.

When the load and pressure are at a desired condition, nut 11 may betightened by hand or automatically as described above to “finger tight”.

The pressure may then be reduced to a desired level and approaches thecalibrated level of the Pressure Buffer Switch (to coincide with the“set” pressure of the unit), the upper prox switch will trip “off”letting the system know to stop the adjustment of pressure.

Although aspects of the present invention were described above withrespect to their application to wheel hub assemblies, for example, truckwheel hub assemblies, it is understood that aspects of the presentinvention may be applied to any vehicle, machine, or component having atleast one bearing. Further, although press mechanism 44 is describedabove as applying a compressive load to an inner race of a bearing, suchload could be applied elsewhere to the bearing or wheel assembly 10 suchthat a frictional or other load on a retaining nut is reduced to allowrotation of a retaining nut. Such rotation may allow teeth of the nutand teeth of a keeper to be aligned with each other to allow engagementof a shaft engaging portion (e.g., engaging member 534) of the keeperwith a shaft, (e.g., a shaft slot 5 thereof) to inhibit rotation of thenut relative to the shaft.

While several aspects of the present invention have been described anddepicted herein, alternative aspects may be effected by those skilled inthe art to accomplish the same objectives. Accordingly, it is intendedby the appended claims to cover all such alternative aspects as fallwithin the true spirit and scope of the invention.

The invention claimed is:
 1. A method for use in providing a load on abearing mounted to a shaft, the method comprising: mounting an attachingmember to an end of the shaft; coupling a press mechanism to theattaching member, the press mechanism configured to provide acompressive load to the bearing; coupling the press mechanism to asource of fluid; providing a pressure of the fluid from the source tothe press mechanism to provide the compressive load to the bearing andchanging the pressure of the fluid; the changing the pressure of thefluid causing a piston of a switch of the press mechanism to extend froma base of the switch past a first proximity sensor of the switch to tripa second proximity sensor of the switch; and the switch controlling thepressure of the fluid to control the load on the bearing in response tothe piston tripping the second proximity sensor.
 2. The method of claim1 wherein the switch controlling the pressure of the fluid to controlthe load on the bearing in response to the piston tripping the secondproximity sensor comprises the switch inhibiting an increase in pressureto inhibit an increase of the load.
 3. The method of claim 1 furthercomprising the piston retracting toward the base in response to adecrease in the pressure of the fluid and the piston tripping the firstproximity sensor of the switch, the switch controlling the pressure ofthe fluid to control the load on the bearing in response to the pistontripping the first proximity sensor.
 4. The method of claim 3 whereinthe controlling the pressure comprises the switch inhibiting thedecrease in the pressure in response to the piston tripping the firstproximity sensor.
 5. The method of claim 1 further comprising the pistontripping the first proximity sensor of the switch in response to adecrease in the pressure and the switch inhibiting the decrease in thepressure in response to the piston tripping the first proximity sensor.6. The method of claim 1 wherein the providing the compressive load tothe bearing comprises providing the load by a plurality of extensions ofthe press mechanism by engaging the extensions with an inner race of thebearing.
 7. The method of claim 1 further comprising engaging a lock nutwith the shaft and rotating the lock nut to a particular position by anelectronically controlled wrench to achieve a desired preload or endplaysetting on the bearing.